Prediction models for the thermal conductivity of aqueous starch

The objectives of this research were to determine the thermal conductivity of aqueous starch and to develop a theoretical model to predict the thermal conductivity for both granular and gelatinized aqueous starches. Thermal conductivity of starch was experimentally investigated as a function of moisture content (55-70%) and temperature (5-45degreesC) by using the probe method. Six structural heat conduction models were employed to predict the thermal conductivity. Results indicated that the experimental thermal conductivity increased with increasing moisture content and temperature for both granular and gelatinized starch. The effect of gelatinization on thermal conductivity was small but significant at 5degreesC, but insignificant at 25 and 45degreesC. Over the moisture and temperature ranges investigated, the thermal conductivity values predicted by the Kopelman (B) and Maxwell models were in close agreement with the experimental values for granular starch, whereas for gelatinized starch, the Maxwell model yielded the lowest standard error with the experimental values.